The present invention concerns a touch pad construction such touch pads being used in timing swimming competitions and being arranged to be mounted on one wall of the swimming pool. Basically, such touch pads comprise a striker plate and at least one electric contact cable. When a swimmer comes into contact with the striker plate the motion thereof causes a contact within the cable to be closed thereby providing signals to a suitable measuring apparatus.
Known touch pad constructions include among others an arrangement such as shown for example in U.S. Pat. Nos. 3,590,181 or 3,745,275. In the first of these a series of elongated panels are mounted side by side in a hinged manner along the length of a supporting bar. These panels are thus substantially independent of one another and reaction thereof may tend to be somewhat irregular. Since each such panel, moreover, must be provided with an individual switch the arrangement tends to become quite expensive. In the arrangement as shown in U.S. Pat. No. 3,745,275 the entire touch pad striker plate is made of a single integrally formed panel. To achieve the required rigidity and at the same time retain other desirable characteristics such single integrally formed touch pads were made by the lamination and hot pressing together of three sheets and the assembly was thereafter provided with holes which in such case appear necessary to prevent the wave motion occurring within the swimming pool from accidentally triggering the switching arrangements. Such a construction was both heavy and rather costly.
The present invention has as its purpose to overcome the disadvantages of these and similar prior art constructions through the use of a built-up panel using as base elements a series of identical panels which may be assembled together in a particularly simple manner so as to provide the finished article of any desired size within certain limits. It has been found that the arrangement according to the invention, moreover, provides the necessary rigidity and sensitivity whilst at the same time providing further the advantages of the pierced construction shown in U.S. Pat. No. 3,745,275.
Furthermore, in effect owing to the mounting and assembling arrangement, each individual panel may undergo a slight rotational motion and this has been found to give an improved touch sensitivity. In respect of the assembled arrangement according to the invention one fixed point is at the bottom and this ensures that a very small amount of flexion is sufficient to ensure contact using only two contact sleeves. In the prior art arrangement as many as five sleeves have been necessary.
It is readily evident that the novel arrangement according to the invention will be much lighter than earlier arrangements and owing to this particular construction it has been found that for the same area of surface the price will be about half that of the known constructions.